Low-Temperature Behaviors of Phonon-Limited Electron Mobility of Sub-10-nm-Thick Silicon-on-Insulator Metal–Oxide–Semiconductor Field-Effect Transistor with (001) and (111) Si Surface Channels

Abstract

In this study we simulate the impact of silicon layer thickness and temperature on the phonon-limited electron mobility of the inversion layer for ultrathin-body ( 111) and ( 001) surface silicon-on-insulator (SOI) layers in single-gate (SG) and double-gate (DG) SOI metal-oxidesemiconductor field-effect transistors (MOSFETs); one-dimensional self-consistent calculations and relaxation time approximations are performed. For a sub-10-nm-thick SOI layer, it is demonstrated that intra-subband phonon scattering at the lowest subband in the inversion layer on the (111) Si surface of the DG SOI MOSFET is strongly suppressed in a medium-to-high effective field (E eff ) at a low temperature. On the other hand, it is revealed that the contribution of inter-subband phonon scattering in the inversion layer on the (001) Si surface of the DG SOI MOSFET is very large in a medium-to-high E eff regardless of temperature. Simulation results suggest that the phonon-limited electron mobility on the (111) Si surface of the DG MOSFET will be highly advantageous for future high-performance low-temperature device applications including space applications.

Temperature Dependence of Electron Mobility in Uniaxial Strained nMOSFETs

“…In addition, the phonon scattering mobility (µ ph ), coulomb mobility (µ coul ) and surface roughness mobility (µ sr ) on the (100)/<110> Si surfaces were also calculated through our solver. To consider the physical mechanism of mobility enhancement in strained nMOSFETs, we take the intravalley and intervalley phonon scattering into account [6,8]. The traditional theory of intravalley and intervalley phonon scattering has already been developed and expressions for the momentum relaxation rate have been obtained.…”

“…The strain changes the electronic band structure resulting in the change of carrier mobility [1][2][3][4][5]. While the electrostatics of strained MOSFETs has been studied, several research groups have reported the mobility characteristic in strained MOSFETs [1,6] or in unstrained MOSFETs [7,8]. It is also reported that the intervalley phonon scattering is required to accurately explain the behavior of inversion layer mobility in both strained and unstrained Si MOSFETs [9].…”